Process for producing fluorides of metals

ABSTRACT

Process for producing fluorides of Mo, W, Nb, Ta, V, Re, Ti, Zr, Hf, Co, Ni, Cr, Sb, Sn, Zn, Pb, Al and rare earth metals comprising heating fluorine-containing ammonium salts of corresponding metals in a stream of an inert or reducing gas to convert them into fluorides of the metals.

This is a continuation of application Ser. No. 713,440, filed Mar. 19,1985, abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a process for producing fluorides ofMo, W, Nb, Ta, V, Re, Ti, Zr, Hf, Co, Ni, Cr, Sb, Sn, Zn, Pb, Al andrare earth metals.

2. Description of the Prior Art

So far, fluorides of these metals (Mo, W, Nb, Ta, V, Re, Ti, Zr, Hf, Co,Ni, Cr, Sb, Sn, Zn, Pb, Al and rare earth metals) have been preparedgenerally by reacting F gas with purified metals as shown below.

    Mo+3F.sub.2 →MoF.sub.6

    W+3F.sub.2 →WF.sub.6

    Nb+2.5F.sub.2 →NbF.sub.5

    Ta+2.5F.sub.2 →TaF.sub.5

    V+2.5F.sub.2 →VF.sub.5

    Re+3F.sub.2 →ReF.sub.6

    La+1.5F.sub.2 →LaF.sub.3

    Ce+1.5F.sub.2 →CeF.sub.3

    Nd+1.5F.sub.2 →NdF.sub.3

    Sm+1.5F.sub.2 →SmF.sub.3

    Eu+1.5F.sub.2 →EuF.sub.3

    Gd+1.5F.sub.2 →GdF.sub.3

    Tb+2F.sub.2 →TbF.sub.4

    Tm+1.5F.sub.2 →TmF.sub.3

    Lu+1.5F.sub.2 →LuF.sub.3

    Y+1.5F.sub.2 →YF.sub.3

    Sc+1.5F→ScF.sub.3

    Ti+2F.sub.2 →TiF.sub.4

    Zr+2F.sub.2 →ZrF.sub.4

    Hf+2F.sub.2 →HfF.sub.4

    Co+F.sub.2 →CoF.sub.2

    Ni+F.sub.2 →NiF.sub.2

    Cr+11/2F.sub.2 →CrF.sub.3

    Sb+11/2F.sub.2 →SbF.sub.3

    Cd+F.sub.2 →CdF.sub.2

    Sn+2F.sub.2 →SnF.sub.4

    Zn+F.sub.2 →ZnF.sub.2

    Pb+F.sub.2 →PbF.sub.2

    Al+11/2F.sub.2 →AlF.sub.3

There is a further method, other than above, for producing fluorides ofthe metals in which purified oxides of the metals react with F₂ gas.However, the produced fluorides must be very expensive because of thehigh costs of the metals, metal oxides and the expensive F₂ gas.

SUMMARY OF THE INVENTION

The present invention provides a process for producing high purity metalfluorides directly from naturally occurring mineral resources orindustrial exhausts, instead of employing expensive raw materials. Thisinvention overcomes difficulties of previous processes such astime-consuming operation and high costs.

The essence of this invention lies in the method in whichfluorine-containing ammonium salts of Mo, W, Nb, Ta, V, Re, Ti, Zr, Hf,Co, Ni, Cr, Sb, Sn, Zn, Pb, Al and rare earth metals are heated fordecomposition in a stream of an inert or reducing gas, to producefluorides of respective metals as shown hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of the stage for producing metal fluorides of thepresent invention and

FIG. 2 is a diagram of the stage for extracting the fluorine-containingammonium salts used in this invention as the starting materials.

DETAILED DESCRIPTION OF THE INVENTION

The rare earth metals in this invention refer to lanthanum (La), cerium(Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm),europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium(Ho), erbium (Er), thulium (Tm), ytterbium (Yb), luthetium (Lu), yttrium(Y) and scandium (Sc).

    (NH.sub.4).sub.2 MoF.sub.8 →2NH.sub.4 F+MoF.sub.6

    (NH.sub.4).sub.2 MoOF.sub.6 →2NH.sub.4 F+1/2MoF.sub.6 +1/2MoO.sub.2 +1/2F.sub.2

    (NH.sub.4).sub.2 WF.sub.8 →2NH.sub.4 F+WF.sub.6

    NH.sub.4 WOF.sub.5 →NH.sub.4 F+1/2WF.sub.6 +1/2WO.sub.2 +1/2F.sub.2

    (NH.sub.4).sub.2 NbF.sub.7 →2NH.sub.4 F+NbF.sub.5

    (NH.sub.4).sub.2 NbOF.sub.5 →2NH.sub.4 F+1/2NbF.sub.5 +1/2NbO.sub.2 +1/4F.sub.2

    (NH.sub.4).sub.2 TaF.sub.7 →2NH.sub.4 F+TaF.sub.5

    NH.sub.4 VOF.sub.4 →NH.sub.4 F+1/2VF.sub.4 +1/2VO.sub.2 +1/2F.sub.2

    (NH.sub.4).sub.2 VOF.sub.5 →2NH.sub.4 F+1/2VF.sub.5 +1/2VO.sub.2 +1/4F.sub.2

    (NH.sub.4).sub.2 ReF.sub.6 →2NH.sub.4 F+ReF.sub.4

    (NH.sub.4).sub.2 LaF.sub.5 →2NH.sub.4 F+LaF.sub.3

    (NH.sub.4).sub.3 CeF.sub.6 →3NH.sub.4 F+CeF.sub.3

    (NH.sub.4).sub.2 NdF.sub.5 →2NH.sub.4 F+NdF.sub.3

    (NH.sub.4).sub.3 SmF.sub.6 →3NH.sub.4 F+SmF.sub.3

    (NH.sub.4).sub.3 EuF.sub.6 →3NH.sub.4 F+EuF.sub.3

    (NH.sub.4).sub.3 GdF.sub.6 →3NH.sub.4 F+GdF.sub.3

    (NH.sub.4).sub.2 TbF.sub.6 →2NH.sub.4 F+TbF.sub.4

    NH.sub.4 TmF.sub.4 →NH.sub.4 F+TmF.sub.3

    NH.sub.4 LuF.sub.4 →NH.sub.4 F+LuF.sub.3

    NH.sub.4 YF.sub.4 →NH.sub.4 F+YF.sub.3

    NH.sub.4 ScF.sub.4 →NH.sub.4 F+ScF.sub.3

    (NH.sub.4).sub.2 TiF.sub.6 →2NH.sub.4 F+TiF.sub.4

    (NH.sub.4).sub.2 TiF.sub.5 →2NH.sub.4 F+TiF.sub.3

    (NH.sub.4).sub.2 ZrF.sub.6 →2NH.sub.4 F+ZrF.sub.4

    (NH.sub.4).sub.3 ZrF.sub.7 →3NH.sub.4 F+ZrF.sub.4

    (NH.sub.4).sub.2 HfF.sub.6 →2NH.sub.4 F+HfF.sub.4

    (NH.sub.4).sub.3 HfF.sub.7 →3NH.sub.4 F+HfF.sub.4

    (NH.sub.4).sub.2 CoF.sub.4 →2NH.sub.4 F+CoF.sub.2

    (NH.sub.4).sub.2 NiF.sub.4 →2NH.sub.4 F+NiF.sub.2

    (NH.sub.4).sub.2 SnF.sub.6 →2NH.sub.4 F+SnF.sub.4↑

    (NH.sub.4).sub.3 SbF.sub.6 →3NF.sub.4 F+SbF.sub.3↑

    (NH.sub.4).sub.3 CrF.sub.6 →3NH.sub.4 F+CrF.sub.3

    (NH.sub.4).sub.2 CdF.sub.4 →2NH.sub.4 F+CdF.sub.2

    (NH.sub.4).sub.2 PbF.sub.4 →2NH.sub.4 F+PbF.sub.2

    (NH.sub.4).sub.2 ZnF.sub.4 →2NH.sub.4 F+ZnF.sub.2

    (NH.sub.4).sub.3 AlF.sub.6 →3NH.sub.4 F+AlF.sub.3

There are other fluorine-containing ammonium salts suitable for theprocess, other than those listed above. Industrially the salts may beimpure crystals, and actually they are often in the form of a mixture ormay be a mixture of salts of different valencies.

The composition of the fluorine-containing ammonium salts is notdefinite, or rather different depending on the aqueous solutions fromwhich corresponding fluorine-containing ammonium salts are formed.Therefore, the present invention is not restricted by the reactionformulae above. When the atmosphere of heating and decomposition isformed by a stream of a reducing gas and the decomposition is carriedout at a temperature between 150° to 600° C. (150° to 1000° C. forfluorine-containing ammonium salts of Ti, Zr, Hf, Co, Ni, Cr, Sb, Cd,Sn, Zn, Pb and Al) where the temperature is insufficient to cause metalformation, the same reactions could be obtained as in a stream of aninert gas to prepare various fluorides.

The NH₄ F obtained by thermal decomposition in a stream of an inert orreducing gas remains in a gaseous form at a higher temperature, but issolidified at a temperature below 200° C., so it is removed for recoveryfrom the decomposition gas by a known method such as separation byfiltration. The recovered NH₄ F can thus be recirculated to theproducing stage for fluorine-containing ammonium salts of metals.

The fluorine-containing ammonium salts of metals to be used in thisinvention can be prepared, for example, as shown below.

The metal ions of Mo, W, Nb, Ta, V, Re, Ti, Zr, Hf, Co, Ni, Cr, Sb, Sn,Zn, Pb, Al and the rare earth metals including complex ions of the samemetals, which have been extracted and contained in an organic solventcomprising at least one extracting agent selected from the groupconsisting of alkylphosphoric acids, ketones, carboxylic acids, neutralphosphoric acid esters, oximes, and primary through quaternary amines,which solvent may optionally contain a petroleum hydrocarbon as diluent,are brought into contact with an aqueous solution containing both F⁻ andNH₄ ⁺ ions, to separate metal ammonium fluorides from the aqueoussolution and to regenerate the organic solvents at the same time.

    R.sub.6.Mo+6NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.2 MoF.sub.8 +6R.H+4NH.sub.4 F

    H.sub.2 MoO.sub.4.2TBP+3NH.sub.4 HF.sub.2 ⃡(NH.sub.4) .sub.2 MoOF.sub.6 +2TBP+NH.sub.4 OH+2H.sub.2 O

    R.sub.6 W+6NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.2 WF.sub.8 +6R.H+4NH.sub.4 F

    R.sub.3 NH.WO.sub.3 +2NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.2 WOF.sub.5 +2R.sub.3 N+2H.sub.2 O

    H.sub.2 NbF.sub.7.2TBP+4NH.sub.4 OH⃡(NH.sub.4).sub.2 NbOF.sub.5 +2NH.sub.4 F+3H.sub.2 O+2TBP

    H.sub.2 TaF.sub.7.2TBP+2NH.sub.4 F⃡(NH.sub.4).sub.2 TaF.sub.7 +2TBP.HF

    R.sub.4.V+2NH.sub.4 HF.sub.2 +H.sub.2 O⃡(NH.sub.4).sub.2 VOF.sub.4 +4RH

    (R.sub.3 NH)VO.sub.3 +3NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.2 VOF.sub.5 +R.sub.3 N+NH.sub.4 F+2H.sub.2 O

    (R.sub.3 NH).sub.2 ReO.sub.3 +3NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.2 ReF.sub.6 +2R.sub.3 N+2H.sub.2 O+NH.sub.4 OH

    R.sub.3 La+3NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.3 LaF.sub.6 +3R.H

    R.sub.3 Ce+3NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.3 CeF.sub.6 +3R.H

    R.sub.4 Pr+4NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.2 PrF.sub.6 +4R.H+2NH.sub.4 F

    R.sub.3 Nd+3NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.3 NdF.sub.6 +3R.H

    R.sub.3 Sm+3NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.3 SmF.sub.6 +3R.H

    R.sub.3 Eu+3NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.3 EuF.sub.6 +3R.H

    R.sub.3 Gd+3NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.3 GdF.sub.6 +3R.H

    R.sub.4 Tb+3NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.3 TbF.sub.6 +3R.H

    R.sub.3 Tm+3NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.3 TmF.sub.6 +3R.H

    R.sub.3 Lu+3NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.3 LuF.sub.6 +3R.H

    R.sub.3 Y+3NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.3 YF.sub.6 +3R.H

    R.sub.3 Sc+3NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.3 ScF.sub.6 +3R.H

    R.sub.4 Ti+3NH.sub.4 HF.sub.2 ⃡(MH.sub.4).sub.2 TiF.sub.6 +3R.H+R.NH.sub.4

    R.sub.2 TiO+4NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.2 TiF.sub.6 +2R.H+H.sub.2 O+2NH.sub.4 F

    R.sub.3 Ti+3NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.2 TiF.sub.5 +3R.H+NH.sub.4 F

    R.sub.4 Zr+4NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.2 ZrF.sub.6 +4R.H+2NH.sub.4 F

    H.sub.2 ZrF.sub.6.nTBP+2NH.sub.4 F⃡(NH.sub.4).sub.2 ZrF.sub.6 +nTBP+2HF

    (R.sub.3 NH).sub.2 ZrO(SO.sub.4).sub.2 +6NH.sub.4 F⃡(NH.sub.4).sub.2 ZrOF.sub.4 +2R.sub.3 NH.F+2(NH.sub.4).sub.2 SO.sub.4

    R.sub.2 Co+2NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.2 CoF.sub.4 +2R.H

    R.sub.2 Ni+2NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.2 NiF.sub.4 +2R.H

    R.sub.3 Cr+3NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.3 CrF.sub.6 +3R.H

    (R.sub.3 NH)SbO.sub.2 +3NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.3 SbF.sub.6 +R.sub.3 N+2H.sub.2 O

    R.sub.2 Cd+2NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.2 CdF.sub.4 +2R.H

    (R.sub.3 NH).sub.2 SnO.sub.3 +4NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.2 SnF.sub.6 +2R.sub.3 N+3H.sub.2 O+2NH.sub.4 F

    R.sub.2 Zn+2NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.2 ZnF.sub.4 +2R.H

    R.sub.2 Pb+2NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.2 PbF.sub.4 +2R.H

    R.sub.3 Al+3NH.sub.4 HF.sub.2 ⃡(NH.sub.4).sub.3 AlF.sub.6 +3R.H

In the equations, R.H is an H-type extractor.

The metal ions and the metal complex ions transferred to the aqueousphase are converted into corresponding fluorine-containing salts of themetal, which are less soluble than other fluorides of the metal inaqueous solutions and much more rapid in the rate of crystal growth.Consequently, the fluorine-containing ammonium compounds thus formed arereadily separated by filtration.

As has been described before, metal ammonium fluorides thus obtained areheated in a stream of an inert or reducing gas. Then fluorides of thecorresponding metals are produced at a temperature between 150° to 600°C. or between 150° to 1000° C.

NH₄ F or NH₄ HF₂ gas generated from the decomposition can be very easilyrecovered through an absorption or dust collection process. Moreover therecovered gas can be recycled to the production process of metalammonium fluorides.

The alkylphosphoric acids to be used in this invention are selected fromthe group consisting of following compounds: ##STR1## (In the formulae,R is an alkyl group having 4 to 22 carbon atoms in general.)

The compound D₂ EHPA (di-2-ethylhexylphosphoric acid) appearing in theexamples below belongs to Group (a) and the alkyl group is C₈ H₁₇.

Following is an example of the oxime used as extracting agent in thisinvention. ##STR2## (In the formulae, R is H, CH₃, and X is either Cl orH.)

Oximes similar to the above are also useful and a mixture of two or moreoximes such as LIX64N (tradename from Henkel Chemicals) may be used.SME-529 appearing in the Example below is a tradename from ShellChemicals, where R is CH₃ and X is H.

The ketone to be used in this invention is selected from the followinggroups: ##STR3## (In the formula, R and R' are alkyl or aryl groups andusually contain 3 to 22 carbon atoms.)

An example of the ketones appearing in the example is cyclohexanone orthe compound shown below: ##STR4##

The alkyl aryl phosphoric acid used in the present invention is selectedfrom the group having the general formula shown below: ##STR5## whereinR is an alkyl group containing 4 to 15 carbon atoms, A is an aryl group(phenyl group, tolyl group, xylyl group).

OPPA (octyl phenyl phosphoric acid) used in the example is such as R=C₈H₁₇ and X=C₆ H₅.

The carboxylic acids to be used as extracting agent in the presentinvention are selected from the following groups. ##STR6## (In theformulae, R is an alkyl group having in general 4 to 22 carbon atoms.)

The compound V-10 (Versatic-10, tradename from Shell Chemicals)appearing in the Example belongs to Group (a), where the alkyl groupcontains 9 to 15 carbon atoms.

Neutral phosphoric acid esters to be used in this invention are selectedfrom the following groups: ##STR7## (In the formulae, R is an alkylgroup having 4 to 22 carbon atoms.)

Compound TBP (tributylphosphate) used in Example belongs to Group (a),where R is C₄ H₉.

Primary through quaternary amines to be used in this invention areselected from the following groups;

Primary amines RNH₂, where R is an alkyl group having 4 to 25 carbonatoms.

Secondary amines R₂ N-- or R₂ NH, where R is an alkyl group having 4 to25 carbon atoms.

Tertiary amines R₃ N or R₃ NH--, where R is an alkyl group having 4 to25 carbon atoms.

TOA (Trioctylamine) used in Example is expressed by the expressionbelow. ##STR8##

(However, Cl in the formulae could be replaced by another anion.)##STR9##

(In the formula, R is an alkyl group having 4 to 25 carbon atoms.)

The diluents to be used in this invention may be petroleum hydrocarbons,aromatic or aliphatic hydrocarbons, or a mixture thereof. Kerosine, amixture of various hydrocarbons, may even be used. Extracting agentscould be selected from a multiplicity of groups and may be used alone orin a mixture. The selection and the mixing ratio of extracting agentsdepend on the nature of the aqueous solution to be applied and thenature and proportion of suspected impurities. Concentrations ofextracting agent are similarly determined, but usually a concentrationranging from 2 to 100% (by volume) is preferred.

The F⁻ ion containing solution to be used in the present inventioncontains one or more species selected from the group consisting of NH₄HF₂, NH₄ F optionally plus HF. The solution preferably contains a moleratio of F⁻ /NH₄ ⁺ =1/1˜1/0.2 in mole. Further it may contain a reducingagent such as hydrazine, depending on the condition for crystallization.

Inert gases to be used in this invention include argon, helium andnitrogen either alone or in the form of a mixed gases.

Reducing gases to be used in this invention are hydrogen, carbonmonoxide and the vapor of hydrocarbons.

Following is a detailed explanation of this invention with reference tothe drawings. However, this invention is not restricted to the drawings.

The flow-sheet in FIG. 1 shows a basic process in which fluorides (D) ofmetals selected from the group consisting of Mo, W, Nb, Ta, V, Re, Ti,Zr, Hf, Co, Ni, Cr, Sb, Sn, Zn, Pb, Al and the rare earth metals areproduced from metal ammonium fluorides (A) of corresponding metals byheating the latter to a temperature between 150° to 600° C. or 150° to1000° C. in a stream of an inert or reducing gas (C) in the heatingdecomposition stage (B).

The gas produced in the heating and decomposition stage (B) contains NH₄F, which is solidified by cooling, and separated (E) by a known method,to obtain metal fluorides (D). The recovered NH₄ F is recirculated tothe stage in which metal ammonium fluorides are produced.

The flow-sheet in FIG. 2 is a basic process for preparing metal ammoniumfluorides.

Organic solvents (F) which extract and contain simple and complex ionsof a metal selected from the group consisting of Mo, W, Nb, Ta, V, Re,Ti, Zr, Hf, Co, Ni, Cr, Sb, Sn, Zn, Pb, Al and the rare earth metals arebrought into contact with an aqueous solution (G) containing NH₄ ⁺ andF⁻ ions in the stripping stage (H), to transfer the metal and the metalcomplex ions into the aqueous phase and to regenerate the organicsolvents for circulation in the extraction stage. The simple and complexions of metals selected from the group consisting of Mo, W, Nb, Ta, V,Re, Ti, Zr, Hf, Co, Ni, Cr, Sb, Sn, Zn, Pb, Al and the rare earth metalscontained in the aqueous phase are separated in the crystallizationstage (J), to obtain crystals of the metal ammonium fluorides.

The present invention will be explained with reference to the examples.

EXAMPLE 1

Each of the samples shown in Table 1 were placed in an annular electricfurnace and heated in a nitrogen stream flowing at a rate of 3 cc/min.

EXAMPLE 2

Each of the samples shown in Table 2 were placed in an annular electricfurnace and heated in a nitrogen stream flowing at a rate of 0.3l/minute.

The residues shown in the Table are considered to have been formed byhydrogen bonding in part of the crystals due to the presence of (NH₄)₂ZrF₆ OH₂. The residues were identified to be oxides. The volatilematters were determined by identifying the condensate obtained bycooling.

The zero gram in the column of the residue weight means all of thecrystal volatilized.

EXAMPLE 3

Each of the samples shown in Table 3 were placed in an annular electricfurnace and heated in a nitrogen stream flowing at a rate of 0.3l/minute. The volatile matters and the condensates in the table weredetermined by maintaining the gas coming out of the system at about 230°C. and separating NH₄ F and NH₄ HF₂ by utilizing the differences invapor pressure.

REFERENCE EXAMPLE

The metal ammonium fluorides to be used as the starting material in thisinvention may be prepared by known methods of extraction and strippingusing the organic solvents and the stripping solutions as listed inTables 4 to 6.

In the tables, concentration of organic solvents are expressed inpercentages by volume.

The rate of stripping is the percentage of the amount of substanceswhich are transferred into the aqueous phase by a single contact whenequal volumes of aqueous and organic phases are used. The stripping wasconducted in each case at a temperature between 25° to 28° C., and theshaking continued for 10 minutes.

The materials formed were examined by the X-ray diffraction analysis orchemical analysis.

MIBK means methylisobutylketone.

                                      TABLE 1                                     __________________________________________________________________________                            Residue  Volatile matter                              Sample  Weight                                                                            Temperature of heating                                                                    Formula                                                                            Weight                                                                            Formula Weight                               __________________________________________________________________________    NH.sub.4 MoOF.sub.5                                                                   10 g                                                                              350° C.                                                                            MoO.sub.2                                                                          2.8 g                                                                             MoF.sub.6 + NH.sub.4 F                                                                4.6 g                                NH.sub.4 WOF.sub.5                                                                    "   300° C.                                                                            WO.sub.2                                                                           3.4 g                                                                              WF.sub.6 + NH.sub.4 F                                                                4.8 g                                (NH.sub.4).sub.2 NbOF.sub.5                                                           "   450° C.                                                                            NbO.sub.2 F                                                                        3.2 g                                                                              NbF.sub.5 + NH.sub.4 F                                                               4.2 g                                (NH.sub.4).sub.2 TaF.sub.7                                                            "   250° C.                                                                            none   0 g                                                                             .sup. TaF.sub.5 + NH.sub.4 F                                                          7.9 g                                (NH.sub.4).sub.2 VOF.sub.4                                                            "   400° C.                                                                            VO.sub.2                                                                           2.3 g                                                                               VF.sub.4 + NH.sub.4 F                                                               3.5 g                                (NH.sub.4).sub.2 ReF.sub.6                                                            "   280° C.                                                                            ReF.sub.4                                                                          7.8 g                                                                             NH.sub.4 F                                                                            2.2 g                                (NH.sub.4).sub.3 LaF.sub.6                                                            "   420° C.                                                                            LaF.sub.3                                                                          6.3 g                                                                             "       3.7 g                                (NH.sub.4).sub.3 NdF.sub.6                                                            "   450° C.                                                                            NdF.sub.3                                                                          6.4 g                                                                             "       3.6 g                                (NH.sub.4).sub.3 SmF.sub.6                                                            "   400° C.                                                                            SmF.sub.3                                                                          6.5 g                                                                             "       3.5 g                                (NH.sub.4).sub.3 EuF.sub.6                                                            "   300° C.                                                                            EuF.sub.3                                                                          6.5 g                                                                             "       3.5 g                                (NH.sub.4).sub.3 GdF.sub.6                                                            "   350° C.                                                                            GdF.sub.3                                                                          6.6 g                                                                             "       3.4 g                                (NH.sub.4).sub.3 TmF.sub.6                                                            "   400° C.                                                                            TmF.sub.3                                                                          6.7 g                                                                             "       3.3 g                                (NH.sub.4).sub.3 TbF.sub.6                                                            "   250° C.                                                                            TbF.sub.3                                                                          6.6 g                                                                             "       3.4 g                                (NH.sub.4).sub.3 YF.sub.6                                                             "   450° C.                                                                            YF.sub.3                                                                           5.7 g                                                                             "       4.4 g                                __________________________________________________________________________     Remarks:                                                                      In Table 1, the substances left in the ring furnace after heating are         identified and listed by their formula and weight in the column "Residue"     and the "Volatile matters" which were cooled and identified are listed in     the 6th and 7th columns. The "none" in the residue column means complete      evaporation leaving nothing. Blanks in the column "weight" means that the     total weight of the residue could not be recovered.                      

                  TABLE 2                                                         ______________________________________                                                   Temper-           Volatile matter                                                   ature of Residue  For-                                       Sample   Weight  heating  weight   mula  Weight                               ______________________________________                                        (NH.sub.4).sub.2 TiF.sub.6                                                             30 g    400° C.                                                                         TiF.sub.4                                                                          18.8 g                                                                              NH.sub.4 F                                                                          11.2 g                             (NH.sub.4).sub.2 ZrF.sub.6                                                             30 g    500° C.                                                                         ZrF.sub.4                                                                          20.5 g                                                                              NH.sub.4 F                                                                          9.5 g                              (NH.sub.4).sub.2 HfF.sub.6                                                             30 g    500° C.                                                                         HfF.sub.4                                                                          23.1 g                                                                              NH.sub.4 F                                                                          6.9 g                              ______________________________________                                    

                                      TABLE 3                                     __________________________________________________________________________                                     Volatile matter                              Sample Weight                                                                            Temperature of heating                                                                    Residue weight                                                                          Formula Weight                               __________________________________________________________________________    (NH.sub.4).sub.2 CoF.sub.4                                                           30 g                                                                              500° C.                                                                            CoF.sub.2                                                                          17 g NH.sub.4 F                                                                            13 g                                 (NH.sub.4).sub.2 NiF.sub.4                                                           30 g                                                                              500° C.                                                                            NiF.sub.2                                                                          17 g NH.sub.4 F                                                                            13 g                                 (NH.sub.4).sub.3 CrF.sub.6                                                           30 g                                                                              800° C.                                                                            CrF.sub.2                                                                          14.9                                                                             g NH.sub.4 F                                                                            15.1                                                                             g                                 (NH.sub.4).sub.3 SbF.sub.6                                                           30 g                                                                              500° C.   0  g SbF.sub.3 + 3NH.sub.4 F                                                               30 g                                                        (Condensate 18.5 g)                                    (NH.sub.4).sub.2 CdF.sub.4                                                           30 g                                                                              500° C.                                                                            CdF.sub.2                                                                          20.1                                                                             g NH.sub.4 F                                                                            9.9                                                                              g                                 (NH.sub.4).sub.2 SnF.sub.6                                                           30 g                                                                              500° C.   0  g SnF.sub.4 + NH.sub.4 F                                                                30 g                                                        (Condensate 21.7 g)                                    (NH.sub.4).sub.2 ZnF.sub.4                                                           30 g                                                                              500° C.                                                                            ZnF.sub.2                                                                          17.5                                                                              g                                                                              NH.sub.4 F                                                                            12.5                                                                             g                                 (NH.sub.4).sub.2 PbF.sub.4                                                           30 g                                                                              600° C.                                                                            PbF.sub.2                                                                          23 g NH.sub.4 F                                                                            7  g                                 (NH.sub.4).sub.3 AlF.sub.6                                                           30 g                                                                              800° C.                                                                            AlF.sub.3                                                                          12.9                                                                             g NH.sub.4 F                                                                            17.8                                                                             g                                 __________________________________________________________________________

                                      TABLE 4                                     __________________________________________________________________________    Metal                                                                             Organic solvent  Stripping solution                                                                     Rate of stripping                                                                      Example of product                     __________________________________________________________________________    Mo  60% TBP + 40% isoparaffin                                                                      100 g/l                                                                           NH.sub.4 HF.sub.2                                                                  99.5%    (NH.sub.4).sub.2 MoOF.sub.6            W   10% TOA + 90% isoparaffin                                                                      150 g/l                                                                           NH.sub.4 HF.sub.2                                                                  99.8%    NH.sub.4 WOF.sub.5                     Nb  100% MIBK        100 g/l                                                                           NH.sub.4 F                                                                         99.1%    (NH.sub.4).sub.2 NbOF.sub.5            Ta  85% TBP + 15% aromatics                                                                        100 g/l                                                                           NH.sub.4 F                                                                         99.8%    (NH.sub.4).sub.2 TaF.sub.5             V   30% D.sub.2 EHPA + 70% n-paraffin                                                              200 g/l                                                                           NH.sub.4 F                                                                         99.1%    (NH.sub.4).sub.2 VOF.sub.4             Re  80% TBP + 20% isoparaffin                                                                      150 g/l                                                                           NH.sub.4 F                                                                         99.8%    (NH.sub.4).sub.3 ReF.sub.7             La  30% D.sub.2 EHPA + 70% isoparaffin                                                             200 g/l                                                                           NH.sub.4 HF.sub.2                                                                  92.7%    (NH.sub.4).sub.2 LaF.sub.6             Nd  30% V-10 + 70% isoparaffin                                                                     150 g/l                                                                           NH.sub.4 HF.sub.2                                                                  94.1%    (NH.sub.4).sub.3 NdF.sub.6             Sm  30% V-10 + 70% isoparaffin                                                                     150 g/l                                                                           NH.sub.4 HF.sub.2                                                                  94.8%    (NH.sub.4).sub.3 SmF.sub.6             Eu  30% D.sub.2 EHPA + 70% n-paraffin                                                              200 g/l                                                                           NH.sub.4 HF.sub.2                                                                  92.8%    (NH.sub.4).sub.3 EuF.sub.6             Gd  30% D.sub.2 EHPA + 70% n-paraffin                                                              200 g/l                                                                           NH.sub.4 HF.sub.2                                                                  93.3%    (NH.sub.4).sub.3 GdF.sub.6             Tm  30% D.sub.2 EHPA + 70% n-paraffin                                                              200 g/l                                                                           NH.sub.4 HF.sub.2                                                                  94.1%    (NH.sub.4).sub.3 TmF.sub.6             Tb  30% D.sub.2 EHPA + 70% isoparaffin                                                             200 g/l                                                                           NH.sub.4 HF.sub.2                                                                  98.4%    (NH.sub.4).sub.3 TbF.sub.6             Y   65% TBP + 35% isoparaffin                                                                      150 g/l                                                                           NH.sub.4 F                                                                         99.8%    (NH.sub.4).sub.3 YF.sub.6              __________________________________________________________________________

                                      TABLE 5                                     __________________________________________________________________________    Metal                                                                             Organic solvent     Stripping solution                                                                     Rate of stripping                                                                      Example of product                  __________________________________________________________________________    Ti  30% D.sub.2 EHPA + 70% isoparaffin                                                                150 g/l                                                                           NH.sub.4 HF.sub.2                                                                  99.1%    (NH.sub.4).sub.2 TiF.sub.6          Ti  30% V-10 + 70% n-paraffin                                                                         100 g/l                                                                           NH.sub.4 HF.sub.2                                                                  99.9%    (NH.sub.4).sub.2 TiF.sub.6          Zr  10% TOA + 90% aromatic hydrocarbon                                                                100 g/l                                                                           NH.sub.4 F                                                                         99.4%    (NH.sub.4).sub.2 ZrF.sub.6          Zr  60% TBP + 40% isoparaffin                                                                         180 g/l                                                                           NH.sub.4 F                                                                         99.6%    (NH.sub.4).sub.2 ZrF.sub.6                                                    -Hf 100% MIBK 200 g/l NH.sub.4                                                F 94.7% (NH.sub.4).sub.2                                                      HfF.sub.6                           __________________________________________________________________________     (MIBK = methylisobutylketone)                                            

                                      TABLE 6                                     __________________________________________________________________________    Metal                                                                             Organic solvents containing extracted metal values                                                    Stripping solution                                                                     Rate of stripping                                                                      Example of                      __________________________________________________________________________                                                  product                         Co  20% OPPA + 5% SME-529 + 7.5% kerosine                                                                 100 g/l                                                                           NH.sub.4 HF.sub.2                                                                  99.1%    (NH.sub.4).sub.2 CoF.sub.4      Ni  30% D.sub.2 EHPA + 70% isoparaffin                                                                    100 g/l                                                                           NH.sub.4 HF.sub.2                                                                  99.9%    (NH.sub.4).sub.2 NiF.sub.4      Cr  30% D.sub.2 EHPA + 70% kerosine                                                                       300 g/l                                                                           NH.sub.4 F                                                                         56.1%    (NH.sub.4).sub.2 CrF.sub.6      Sb  20% TBP + 80% isoparaffin                                                                             200 g/l                                                                           NH.sub.4 HF.sub.2                                                                    99%    (NH.sub.4).sub.3 SbF.sub.6      Sn  20% TOA + 80% kerosine  100 g/l                                                                           NH.sub.4 F                                                                         98.9%    (NH.sub.4).sub.2 SnF.sub.6      Pb  30% V-10 + 70% n-paraffin                                                                             100 g/l                                                                           NH.sub.4 F                                                                         99.4%    (NH.sub.4).sub.2 PbF.sub.4      Cd  30% D.sub.2 EHPA + 70% aromatic                                                                       150 g/l                                                                           NH.sub.4 HF.sub.2                                                                  99.8%    (NH.sub.4).sub.2 CdF.sub.4      Zn  30% SME-529 + 70% kerosine                                                                            150 g/l                                                                           NH.sub.4 F                                                                         99.2%    (NH.sub.4).sub.2 ZnF.sub.4      Al  30% OPPA + 70% isoparaffin                                                                            100 g/l                                                                           NH.sub.4 HF.sub.2                                                                  99.6%    (NH.sub.4).sub.3 AlF.sub.6      __________________________________________________________________________

What is claimed is:
 1. A process for producing fluorides of Mo, W, Re,Co, Ni, Cr, Sb, Sn, Pb and rare earth metals, comprising bringing anorganic solvent containing ions or complex ions of a metal selected fromthe group consisting of Mo, W, Re, Co, Ni, Cr, Sb, Sn, Pb and rare earthmetals into contact with an aqueous solution containing F⁻ ion and NH₄ ⁺ion to transfer the metal ions or metal complex ions into the aqueousphase, said organic solvent being one selected from the group consistingof alkylphosphoric acid, alkyl aryl phosphoric acids, carboxylic acids,oximes, ketones, neutral phosphoric acid esters, and primary throughquaternary amines, said solvent being diluted with a petroleumhydrocarbon to separate fluorine-containing ammonium salts from saidaqueous solution and to simultaneously regenerate said organic solvent,and heating said fluorine-containing ammonium salts in a stream of inertor reducing gas to decompose said salts into fluorides of thecorresponding metals and form NH₄ F or NH₄ HF₂ gases.
 2. The process ofclaim 1, wherein said aqueous solution contains a mole ratio of F⁻ /NH₄⁺ of about 1/1 to about 1/0.2.
 3. The process of claim 1, wherein saidaqueous solution contains a reducing agent.
 4. The process of claim 3,wherein said reducing agent is hydrazine.
 5. The process of claim 1,wherein said NH₄ F or NH₄ HF₂ gases are recycled to the step in whichsaid organic solvent is brought into contact with said aqueous solution.6. The process of claim 1, wherein said metal ammonium fluorides areheated to between 150° and 1000° C.
 7. The process of claim 1, whereinsaid reducing gases include hydrogen, CO and hydrocarbon vapors.
 8. Theprocess of claim 1, wherein said inert gases include argon, helium,nitrogen and mixtures thereof.
 9. The process of claim 1, wherein saidNH₄ F and NH₄ HF₂ gases are recovered by an absorption or dustcollection step.